Problem: The following line passes through point $(9, 7)$ : $y = 1 x + b$ What is the value of the $y$ -intercept $b$ ?
Explanation: Substituting $(9, 7)$ into the equation gives: $7 = 1 \cdot 9 + b$ $7 = 9 + b$ $b = 7 - 9$ $b = -2$ Plugging in $-2$ for $b$, we get $y = 1 x - 2$. ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${10}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$ ${\llap{-}10}$ ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${10}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$ ${\llap{-}10}$ $(9, 7)$